Electron discharge tube



H. SCHEDEL ELECTRON DISCHARGE TUBE Filed Aug. 25, 1957 May 2s, 1940'.`

Patented May ze, 194e f amano-iff' ELE'oTRoN DISCHARGE TUBE b. H., Berlin, Germany, .aammpanyey N `Application August 25, 19372 SeriaPN?160;'7-719'y In Germany August 26, 1936 v claims. (ci. 22504-215) The invention relates to discharge tubes and the method oi manufacturing them, said .tubes having an envelope or composed of ametal bulb and a cover. v More particularly the invention is 5 concerned with the manner of uniting these ytwo by a seal so as to insure vacuum tightness.

This seal, e. g., of glass, must be` heated in order'to insure tight adherence to the metal bulb. Heating the entire metal bulb however endangers the electrode system. The invention therefore providesfor heating only that part of the bulb to Which the seal must stick, and it attains this object by supplying the necessary heat bythe v seal itself. For this purpose the seal is poured onto the cover and said bulb part, thusbeing applied thereto in a state inwhich it contains the heat necessary for the seal to unite with this bulb part. The portion of the envelope to which the seal is applied is preferably a flange integral '20 with the envelope so as to enhance the effect of the seal applied thereto.

` Examples of the latter kind are representedin Figs. l to 5 each of which is a sectional view illus.- trating one embodiment of the invention..

' 25 In all these examples the metal bulb l` has aange 2 and a thin-Walled `annular body 3 Whose Wall thickness is much smaller than that of the bulb l. Body 3 is fastened to flange 2. 4 denotes a disc-shaped cover which preferably is of :,0 a ceramic material.l 5 indicates a seal byvwhich cover 4 and bulb I are interconnected in a manner to insure vacuum tightness. l

In the arrangement according to Fig. lk the body 3 is part of a ring shaped body 6 which is i Welded to flange 2 with the assistance of a hard solder ring 1. Body 3 `and disc 4 form a Acup to receive the seal 5. Disc 4 has a reduced part 4' by which it joins the body 3. Disc54 and body 3 are flush with each other on the outside.

In the arrangement accordingto Fig. 2'the body 3a is T-shaped and is thin-Walled like foil. Body 3a is Welded directlyto flange Z and at its inner edgel extends over an' annular recess "9 of the bulb I and abuts the disc 4 With'vvhich itv is flush on the outside.

In the arrangement represented 4in Fig. 3 the body 3b is as in the arrangement shown in Fig. l l

la metal such as nickel, iron for an iron-nickel,-

v cobalt alloy and formspart of an .annular body 6 Whose vcross-sectionalA configuration is ap,-r

proximately like the one illustrated in Fig.,1. Disc 4 is of lead glassand has an annular groove IB in its edge portion. Body 6 is provided With an annular recess II. Thereduced parts 4', S thus formed are ush with one another. The

seal 5.

1 to each other.

l bodyl I is of pure iron, andthe flange an ironthere are annular edges supporting the rings 3d. 1o..

Ring 3d is upturned at its outer edge and is at this edgesupported by ange 2. f

vThe seal 5 should be preferably such as to soften between and r900" Celsius. It may be of glass, such` as a glass containing lead, or the 15 like and vmay also be composed of other materials of like nature. Also metals may be employed.v for forming'the seal. The'bodies, 3a, 3d are preferably made of a metahsuch for instance as an iron alloy, iron- 20 nickel .or iron-nickel-cobalt, or may consist of copper, tungsten or. molybdenum, but may be made of other materials adapted to unite with the The bodies, 3a, 3d may be fastened to ange 2 25 by welding, soldering, rolling, or pressing. The 1 rolling or pressing may be `effected in the same yoperation in which bulb I is produced.

If the cover 4 is of a ceramicmaterial it may The seal 5 is pouredonto the parts 4, 3 in an easily fusible state andA thus lls up all hollowsv or joints of the cup-shaped. structure 4, 3. The seal may be applied thereto in a predetermined quantity. The bodies 3 are quickly heated by the 35 hot seal- 5` to temperatures at which they are able so to unite with the seal 5 that they will stick The rapid heating of the bodies 3 is due to the fact that they are thin-walled andis attributable also to the manner in which they are 40 joined to flange 2being so attached thereto that thev smallest possible amount oi heat shall be led away from them. This purpose is served by y f K In this respect recess I0 (Fig. 43) too is helpful.

Instead of covering the disc 4 entirelyvwith the 50 sealthe arrangement may be such that only certain parts thereof shall be covered.

` What is claimed is:

l. An electronicdischarge tube havingan openended metallic envelope,'a metallic iiange sur- 55 (Figs. 4,A 5) which 45 Cri rounding the open end of the envelope, a ceramic closing disc Within said open end and resting on the open end of said envelope, and a vitreous seal covering said disc and flange.

2. An electronic discharge tube having an openended metallic envelope, a thin Walled metallic rim above said open end and having a relatively heavy body portion, means for securing said body portion to said envelope, a ceramic closing disc resting on the open end of said envelope, and a glass seal covering said disc and contacting with said rim.

3. An electronic discharge tube having an open-ended metallic envelope, a flange surrounding the open end of said envelope, a thin walled curved metallic rim having a relatively thicker basal portion, means for securing said basal portion to said flange with open spaces between the two, a closing disc for the open end of said envelope surrounded by said ange and basal portion, and a continuous glass seal covering said disc and contacting with said rim.

4. The method of manufacturing electronic discharge tubes having a metallic envelope, comprising the following steps: applying a closure to the rim of the open end of the tube envelope, and pouring a glass seal over the outside surface of the closure and into contact with the rim of the envelope.

5. The method defined in claim 4 and in Which the closure is heated before the glass seal is poured on it.

HANS SCI-IEDEL. 

